Method for the production of plastic

ABSTRACT

Transport belt for use in the continuous production of plastic covered coils. The belt is made from a current conducting material, such as copper and has a plurality of equally spaced coil mounting projections extending from one edge of the belt and spaced therealong. The projections may have tapered outer ends to accommodate ready mounting of the core for the coil thereon. The belt has contact surfaces on opposite sides of the projections and has slots between the contact surfaces. The wires of the completed coil may be soldered or welded to the contact surfaces as the coil is formed. The belt is then cut in intersecting relation relative to the slots to maintain the wires and contacts connected with the coil and to separate the contacts from each other. As a variation of the invention, the belt may be constructed with parallel belt portions with the mounting rod projections extending inwardly from one belt portion and the contact projections extending inwardly from the other belt portion.

iluited States Eatent n91 Utner 1111 aasmse METHOD FOR THE PRODUCTION OF PLASTIC [76] lnventor: Ferdinand Utner, Roter-Brach-Weg 99, 84 Regensburg, Germany [62] Division of Ser. No 200,124, Nov. 18, 1971.

[56] References Cited UNITED STATES PATENTS 5/1970 Witte l 198/131 3/1971 Berg 206/56 AB Primary Examiner-Richard E. Ae gerter Attorney, Agent, or FirmHill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson 5 7 1 ABSTRACT Transport belt for use in the continuous production of plastic covered coils. The belt is made from a current conducting material, such as copper and has a plurality of equally spaced coil mounting projections extending from one edge of the belt and spaced therealong. The projections may have tapered outer ends to accommodate ready mounting of the core for the coil thereon. The belt has contact surfaces on opposite sides of the projections and has slots between the contact surfaces. The wires of the completed coil may be soldered or welded to the contact surfaces as the coil is formed. The belt is then cut in intersecting relation relative to the slots to maintain the wires and contacts connected with the coil and to separate the contacts fromeach other. As a variation of the invention, the belt may be constructed with parallel belt portions with the mounting rod projections extending inwardly from one belt portion and the contact projections extending inwardly from the other belt portion.

2 Claims, 7 Drawing Figures PATENTEL DEC 1 4 SHEET 10F 2 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to a transport belt for the substantially continuous production of generally cylindrically shaped plastic covered coils having a plugged-type electrical connection useful in circuit boards where they are plugged in on one end and upstand vertically. More specifically the transport belt has a plurality of equally spaced mounting rods for tubular cores through which one of the winding wires is run and connected to connecting current conducting projections on the belt to facilitate the continuous production of the coil is facilitated.

2. Prior Art The use of a plurality of similar or identical coils in printed circuit board constructions used in electronic applications such as fixed value memories, requires that the field of electrical currents flowing throughthe different coils does not become so large as to cause induction voltages in windings on adjacent cores since these induction voltages might effect their operation. The coils thus must have a closed magnetic coupling between the conductor paths and the windings on the coil cores, i.e. the distance between the core and the conductor path must be kept as small as possible. In this type of construction it is usually necessary that rod cores be arranged among the coils in order to guide the lines of the induction fields emerging from the coil cores towards the other side of the coil on well defined paths.

According to prior art methods of making coils a small semiconductor plate is set onto a corresponding surface of a small carrier plate and attached thereto by gluing or welding their contacts onto other strips which are provided for this purpose.

These prior art methods present difficulties when applied to the construction of wound coils. Thus, the sheet metal strips lie along the coil and not only influence the output of the coil but represent a danger to the fine wire of the winding. For example, the German Gebrauchmuster 1,887,373 describes a cylinder-shaped resistor with one cap or clamp respectively at each of its two opposite ends whereby at least one of the caps or clamps is connected with a transporting band means in one piece, during the production process. This method, however, has a severe disadvantage that the cap represents a short circuit winding which could pos sibly weaken the signalsto be transmitted. Another disadvantage is that one of the laterally projecting solder contacts must be slipped over the coil and guided toward the printed circuit thereby requiring that a relatively large distance be provided between the winding which has been placed around the component part and the core after the structure has been coated to become a cylindrical component part. Furthermore, the magnetic coupling between the outer winding and that one which is applied to the core would be very bad with this construction since it would cause a strong influencing of adjacent coils. In addition, providing for connections on both sides of a coil member as illustrated herein it is very difficult according to the prior art and requires complicated embossments and metal working. This is especially true if only one transporting belt means is to be used for the production of both contacts.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art by providing for the production of cylindrically-shaped coils in series which coils have a contact means only on one end and have thin connection wires, in the order of one-tenth of one millimeter diameter, which must be connected mechanically safe and electrically conductive to feed lines. According to the invention this advantageous method comprises the steps of winding an elongated tubular core with an outer wire winding of at least one wire, positioning one end of the wire winding so that it extends through the tubular core whereby the first and second ends of the wire winding are at a first end of the tubular core, mounting this tubular wire wound core on a projecting portion of a transporting i belt means, said belt means having an outer portion which, when separated therefrom, may serve as first and second contact means, connecting the first and second wire ends to separate ones of the contact means, applying a coating generally over the surface of the coil except for portions of the contact means, and separating the outer portion of the transporting belt means to form the coil means.

This method has the advantage of avoiding mechanical stress on the coil during the electrically conductive connecting with the contact surfaces, during the coating of the coil, and during the later insertion into the electrical circuit. Another advantage is that the coils are held by the projecting portion or mounting rod projection without a necessity for enlarging the core elements circumference at various places as was true in the prior art. Moreover, the rectangular cross section of the mounting rod projection results in the advantage that while on the one hand, it can be adapted exactly to the tubular core diameter, it does on the other hand, leave sufficient space to allow threading one end of the wire winding through the core.

The coil is generally cylindrically shaped with a first end of the coil including an enlarged base portion having first and second laterial projections which projections are of a different width are of a width less than a diameter of the cylindrical portion. The first and sec ond projections are each adjacent a contact means. The lateral projection forms a pedestal which may have embedded therein during the coating step one or more component control elements. With this construction each contact surface of the cylindrically shaped coil has a lateral projection of different width cooperating therewith so that the contacts may be easily and accurately positioned in the circuit board. A further feature which is economically incorporated in the coil construction and which avoids adjusting devices when the completed coil is inserted into the circuit board includes a stop which is formed by the free part of the contact surface being preferably bent at a right angle to the remainder of the contact surface.

The transporting belt means according to the inven tion contains a plurality of spaced mounting rod projections extending from one edge of a strip-like member. The mounting rod projection may be of a rectangular cross section taken transverse to the axis thereof. A slit is provided adjacent the mounting rod projection and extends inwardly from the edge whereby when the transporting belt means is cut along a line inwardly and roughly parallel to the edge, the mounting rod projections will be separated from the transporting belt means and the portions of the transporting belt means adjacent the slits will serve as contact surfaces. At least one opening may be cut into the contact surfaces in order to obtain a better mechanical connection between the coating and the contact surfaces. Since the mounting rod projection remains connected with a contact surface the corresponding end of the coil wire may be welded to the projecting pieces of the rod to guarantee a particularly good electrical connection. With this design of the transporting belt the contact surfaces will be separated from each other and the coils may be separated from the transporting belt by means of only one cut. The contacts or contact surfaces are held in the plastic coated base or pedestal in a stable relationship due to the openings in the contact surfaces which the plastic coating will penetrate during the coating process. In a further embodiment of our invention the projecting portion of the transporting belt means may be provided with an internallongitudinally extending slit dividing the projecting portion into first and second parts, which parts are bent away from each other to provide a more stable connection and support for the core during the manufacturing process.

If both coils and unwound rod cores are required, the transporting belt means may be designed to have a first and second separated portion whose distance of separation is adapted generally to the length of the coils and the rod cores. With this construction the second portion of the belt may have an inner edge with a plurality of spaced mounting rods projecting towards the second portion and the second portion may have an inner edge with a plurality of spaced mounting supports generally projecting toward the first portion. The inner edge of the first portion may have indentations therein receiving an end of the coil core. The first and second portions have slits extending inwardly from the inner edges adjacent each mounting rod projection and mounting support whereby when the first and second portions are cut along a line inwardly of and generally parallel to the inner edges it will result that the mounting rods and the mounting supports will be separated from the transporting belt means. A transporting belt means of this design has the advantage of providing particularly good guidance of the coil and rod core because of their central balanced relationship to each other. It also allows a particularly good utilization of the belt material and allows the separation of the-rod core as by means of a first cut along a separation line in the second portion and a simultaneous separation of the coils by a second out along a separation line in the first portion. The mounting rod projections and mounting supports may be attached in groups of particular sizes and may be arranged in predetermined groups in'accordance with the number of coils or rod cores respectively required in a particular application. This greatly facilitates their packing and/or storage.

The mounting support for the rod core on the transporting belt second portion may take the form of a generally T-shaped member consisting of a leg and a cross member extending therefrom with the T-shaped member being attached to the second portion by the leg of the T-shaped member. An adequate support for the rod core is provided by bending the cross member of the T-shaped member into a generally circular shaped portion and bending the leg at right angles to its initial position whereby the leg serves as a stop for the unwound core when it is inserted into the circular shape portion.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure and in which:

FIG. 1 is an elevational view of the coil sub-assembly about to be attached to a transporting belt means wherein the coil is shown in cross section to illustrate how the connection wire is guided through the opening of the central core member;

FIG. 2 is an elevational view of the belt having a coil, shown in cross section, which has been produced according to the method of the invention before the excess portion of the transporting belt means has been separated; I

FIG. 3 is a top view of a completed coil assembly illustrating an exaggerated base construction having lateral projections of different sizes with control elements embedded therein;

FIGS. 4 and 5 illustrate a further embodiment of the mounting rod projection of the transporting belt having an internal slit dividing the projecting portion into first and second parts which are bent away from each other;

F IG. 6 illustrates another embodiment of a transporting belt means according to the invention wherein a recess on a first portion holds a first end of the core and a mounting rod extension on a second portion of the transporting belt holds a second end of the core; and,

FIG. 7 is a top view of just the mounting support of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there may be seen a generally elongated coil means generally indicated at 35 which includes a tubular core 1 surrounded by at least a single layer winding 2 of a single piece of wire having a first end 3 and a second end 6. As shown, the first end 3 of the wire forming the coil 2 is threaded through the tubular core member 1 to provide for both ends of the wire at the first end la of the core 1. As may be seen from a comparison of FIGS. 1 and 2, the tubular core l is forcedover a projecting rod means 4 which rod means is initially integral with a transporting belt means 5. The transporting belt means 5 has indentations 36 and 37 adjacent the mounting rod projection 4 which indentations are generally of a width to receive the first end la of the core member 1. A plurality of slits 7 extend inwardlyfrom an edge 5a of the transporting belt 5 a distance sufficient to extend below a separating cutting line 29. The transporting belt means 5 includes contact surfaces 8 and 9 situated between the slits 7 which contact surfaces have connected thereto the second and first ends of the wire 6 and 3, respectively. Thus, the second end 6 may be welded to the contact portion 8 and the first end of the coil wire may be welded to the contact portion 9. Suitable holes 13 and trical connection between the wires and the contacts 8 and 9.

With the tubular wire wound core 35 mounted on the projecting portion 4 and the first and second ends of the wire electrically connected to the second and first contact portions respectively, the tubular core and a portion of the contact portions 8 and 9 are coated with a plastic electrically insulating material to form a covering generally indicated at 10. Thematerial may be sprayed on with or without a mold. The coating 10 serves to provide a mechanical protection of the windings, of the thin connection wires 3 and 6 (which may be in the order of 1/10 of a millimeter in diameter) and of their connection to the contact portions 8 and 9. By means ofthis method the upper cylindrical portion 11 of the coil has as small a diameter as possible necessary to meet production tolerances. On the other hand, the central cylindrical portion 12 as best seen in FIGS. 2 and 3 has a somewhat larger diameter which is suited for securing the coil 35 in a corresponding opening of a mounting plate against shifting by firm clamping arrangement.

As may be seen in FIG. 3 the coating 10 may provide an enlarged base portion having first and second laterally extending projections 27 and 32 respectively. These projections 27 and 32 may be of a different width, which width is less than the diameter of the central cylindrical portion 12, so that the completed coil 35 may be easily and accurately plugged into a circuit board. Thus, the first laterally extending portion of the base 27 may have a width a whereas the second portion 32 may have a width b so that when the coil is plugged by means of its first end and contacts into a mounting board the contacts will be properly oriented. As shown in FIG. 3 the lateral projections 27 and 32 may be enlarged to include embedded component coil control elements 40 and 41, respectively. These component control elements may be a resistor and/or a diode which, when embedded in the base during the process of making the coil, provide a lower interference sensitivity of the control and a more simple circuit arrangement.

As shown in FIG. 1 the first wire end 3 may be welded at either of points 13 and 14 on the contact portion 9. The point 13 has the advantage that it is on about the same latitude as the point 15 on the contact portion 8 and thereby lends itself better to an automatic welding arrangement. On the other hand, the point 14 is at the connection point of the mounting rod projection 4 and thereby guarantees a particularly small free wave length of the connection wire 3. The wire 3 of course has been shielded by the core 1 throughout its length and this construction is particularly advantageous for thin wires.

The slits 7 in the band5 extendbelow a separation cutting line 29 so that the contact portions 8 and 9 are separated from each other and from the remainder of the belt 5 with only one cut along the separation line 29. As will be most clearly seen in FIG. 2 the coating may extend into the slit 7 to provide a positive insulation between the portions 8 and 9. Also, it will be seen that the contact portions 8 and 9 each include therein a hole means 39 through which the coating 10 will extend to lock the contact portions Sand 9 securely in place. Whereas the contact portion 9 will be securely held by the portion of the projecting rod 4 which will remain in place, the contact portion 8 will benefit from the provision of the hole 39.

In place of the contact portions 8 and 9 as shown in FIG. 1, there may be provided contact means 16 and 17 as shown in FIG. 3. In the latter embodiment the Contact surfaces 16 and 17 may be bent at a generally right angle either at the beginning of the method of making the coil or alternatively after the coil has been separated from a transporting belt 5. The bent portions serve as a stop means to limit the distance which the coil may be inserted into the circuit board.

According to an embodiment of the invention as shown in FIG. 4 the projecting portion 19 of the transporting belt means may be provided with an internal slit 20 dividing the projecting portion 19 into a first part 21 and a second part 22 which parts 21 and 22 are bent away from each other to provide an enlargement of the projecting rod portion. When the core 1 is positioned on this projecting portion it may be seen that greater stability may be provided while at the same time allowing the wire 3 to be threaded through the tubular core.

tions 33 and 34, respectively, that are spaced apart a distance generally equal to the length of a tubular core member 1 as schematically illustrated in dotted lines. This construction is particularly useful where both wound coils 35 and unwound rod cores such as shown at l are needed in the circuit. In this construction the first portion 33 of the transporting belt means has an inner edge 33a with a plurality of indentations therein for receiving a first end la of the rod core 1. In addition slits 7 as shown with respect to the belt 5 may also be provided. The second portion 34 has an inner edge 34a having a plurality of spaced mounting rods 24 positioned thereon to be received in a second end 1b of a mounting rod 1. In addition, the second portion 34 may have a mounting support means generally indicated at 26 also extending from its inner edge 34a and, as shown, spaced between the mounting rod projections 24.

The mounting support means 26 is also shown by itself in a top view in FIG. 7. The mounting support member 26 for the unwound broad core takes the form of a generally T-shaped member consisting of a leg 31 extending from the second portion 34 and having a cross member 30 extending from the end thereof remote from the second portion 34. The cross member 30 may be seen in FIG. 7 to be bent in a generally circular configuration to receive the core member therein and the leg 31 is bent at right angles adjacent its opposite ends whereby the legs serves as a stop for an unwound core when the unwound core is inserted in the circular shaped portion 25. The mounting rod projections 24 as well as the mounting support means 26 will be severed from the second portion of the transporting belt means 34 along a line generally indicated at 28 in FIG. 6 whereby these elements will thus remain with the coils or unwound rod cores. Thus, the portion 26a of the mounting support means 26 may serve as a base plug for insertion of the mounting rod core in a circuit board. The mounting rod cores together with the mounting support 25 will be coated with a plastic coating in the same process as the adjacent coils so that the mounting support 25 will be permanently connected to the rod cores. This two portioned transporting belt means has the advantage of providing stable guidance of the coil and rod cores through the manufacturing process since it serves to secure opposite ends of the coils and cores. It will be understood that the transporting belt 23 may have inner connecting portion 230 extending between the first and second portions of the belt at intervals therealong to assure stability and constant spacing. The belt material may be of an electrical conducting copper of a gauge which supplies sufficient rigidity in accordance with the coil and core sizes. This material allows a particularly good utilization of the belt and provides for ease of separation of the project-- ing portions inside the cutting lines 28 and 29.

From the foregoing it will be understood that with the belt. structure a substantially continuous production of coils may be effected in a series wherein the particular size and number may be arranged in predetermined groups which groups may correspond to the number of coil means and rod cores required in a particular device. The steps in this method include winding a tubular core 1 with an outer wire winding of at least one wire 2, said wire 2 having a first end 3 and a second end 6, positioning or threading the first end 3 'of the wire winding 2 so that it extends through the tubular core 1 whereby the first and second ends 3 and 6 of the wire are at a first end la of the tubular core, mounting this tubular wire wound core 1 on a projecting portion of a transporting belt means either by positioning the core first end la over a mounting rod projection 4 or 19 as shown in FIGS. 1, 2 and 4 or mounting the second end lb of the rod 1 on the mounting rod projection 24 as shown in FIG. 6, connecting the first and second wire ends 3 and 6, respectively, to contact portions 8 and 9 of the belt means 5 or 33, applying a coating of plastic material generally over the surface of the coil and portions of the contact means 8 and 9 as shown in FIG. 2, which coating may be of different thicknesses along the length of the coil and may be enlarged to theextent as shown in FIG. 3 to include control components 40 and 41, for example, and separating the contact portions 8 and 9 together with the mounting rod projections from the transporting belts 5 or 23 along the separating cutwish to embody within the scope of the patent war ranted hereon all such modifications as might'reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A transporting belt means for the continuous production of plastic covered coils, each coil having a tubular core member, said belt comprising two generally parallel first and second portions spaced apart a distance generally equal to the length of the tubular core members, said first portion of said belt having an inner edge with a plurality of spaced mounting supports projecting toward said second portion and said second portion having a plurality of spaced mounting rods generally projecting toward said first portion, said mounting rods and said mounting supports being alternately spaced, said first portion having contact portions on said inner edge facing said mounting rods and arranged alternately of said mounting rods on said second portion, said first and second portions extending inwardly from said inner edge on opposite sides of each contact portion, each mounting rod and each mounting support being arranged to accommodate said first and second portions tobe cut along lines inwardly of and roughly parallel to the inner edges thereof whereby said mounting rods and mounting supports will be separated from said transporting belt means.

2. A transporting belt means according to claim 1 wherein said contact portions mounting rods and mounting supports are positioned along said first and second portions in predetermined groups, said groups corresponding to the number of coil means and rod core required in a, particular device. 

1. A transporting belt means for the continuous production of plastic covered coils, each coil having a tubular core member, said belt comprising two generally parallel first and second portions spaced apart a distance generally equal to the length of the tubular core members, said first portion of said belt having an inner edge with a plurality of spaced mounting supports projecting toward said second portion and said second portion having a plurality of spaced mounting rods generally projecting toward said first portion, said mounting rods and said mounting supports being alternately spaced, said first portion having contact portions on said inner edge facing said mounting rods and arranged alternately of said mounting rods on said second portion, said first and second portions extending inwardly from said inner edge on opposite sides of each contact portion, each mounting rod and each mounting support being arranged to accommodate said first and second portions to be cut along lines inwardly of and roughly parallel to the inner edges thereof whereby said mounting rods and mounting supports will be separated from said transporting belt means.
 2. A transporting belt means according to claim 1 wherein said contact portions mounting rods and mounting supports are positioned along said first and second portions in predetermined groups, said groups corresponding to the number of coil means and rod core required in a particular device. 